An aluminum radiator is formed by stacking of many aluminum sheets. An aluminum copper radiator is formed by copper heat pipes tightly plugging in the aluminum radiator. Since the weldability of aluminum is poor, it is necessary to plate a layer of weldable alloy of nickel-phosphorus on the location where the aluminum or aluminum copper radiator connects with the main frame, so that the above-mentioned aluminum radiator or aluminum copper radiator can connect with the main frame by weld.
On the aluminum surface, it is easy to form a natural film, which is not good for the electroplating or chemical plating. For the electroplating or chemical plating on the aluminum surface, which must have preplating for the latter plating. The current regular preplating is a double galvanization technique. See the attached FIG. 1 of the current ordinary chemical plating of nickel-phosphorus alloy. The procedures are described as follows:
Step 1: degreasing, removing the oil stain on the radiator surface.
Step 2: water rinsing, cleaning the radiator.
Step 3: weak erosion, putting the radiator in the lye and conducting weak erosion on the radiator surface.
Step 4: water rinsing, cleaning the radiator.
Step 5: acid liquor washing for surface brightness, putting the radiator in the acid liquor until its surface appears bright.
Step 6: water rinsing, cleaning the radiator;
Step 7: first galvanization, putting the radiator in the lye containing zincates for the first galvanization.
Step 8: water rinsing, cleaning the radiator
Step 9: removing the zinc, putting the radiator in acid liquor for zinc removal.
Step 10: water rinsing, cleaning the radiator;
Step 11: second galvanization, putting the radiator in a lye containing zincates for the second galvanization;
Step 12: Water rinsing, cleaning the radiator;
Step 13: chemical plating nickel and phosphor alloy, putting the radiator in a chemical plating trough of nickel, chemical plating the nickel and phosphor on the radiator surface.
Step 14: Water rinsing, cleaning the radiator;
Step 15: drying the radiator
Step 16: parching the radiator
Step 17: finished products
The above process flow can be simplified as: preplating 1, galvanization 2, chemical plating nickel-phosphorus alloy and post-treatment 3, and finished products 4.
After the radiator is chemical plated with nickel-phosphorus alloy, the whole aluminum or aluminum copper radiator is plated with nickel-phosphorus alloy, including the welding section and the non-welding section of the radiator; the non-welding section of the radiator does not need plating. The costs for nickel and phosphor alloy are expensive, which causes the price of aluminum or aluminum copper radiators stay high as always.